Australian rules football playing field



An Australian rules football playing field is a venue where Australian rules football is played.

The playing field is typically a large oval-shaped grass surface, usually a modified cricket field, hence often known as an oval. These fields may vary especially for variations of the game. However, for official Australian Football League matches, strict requirement specifications must be met for stadiums.

Ground dimensions
Australian rules football grounds, even at the highest level of the game, have no fixed dimensions. For senior football, the playing field is an oval between 135 - 185 m long goal-to-goal and 110 - 155 m wide wing-to-wing. Grounds can vary from long and narrow to almost circular, and are not necessarily symmetrical, depending upon how and where the field was constructed. At least 5 m of space between the boundary line and any fence is required for safety.

Smaller fields are generally used for junior football; some are purpose-built, and some are temporarily marked out within the confines of full-sized oval; as for a senior match, there are no fixed dimensions for a junior-sized field. The Western Australian Football Commission advises that a good rule of thumb is to set the length of the field equivalent to $3 1/2$ times the length of an average kick of the age group playing.

By definition in the laws of the game, the portion of the field inside the goal line and boundary lines is called the playing surface. The combination of the playing surface and the space between the boundary line and any perimeter fence, as well as any gaps in the perimeter fence, is called the arena.

Ground markings
A top-level Australian rules football ground has the following markings:
 * Two goal-lines, one at each end of the field, which are straight and 19.2 m long, and contain the goal posts and behind posts. This the area through which points are scored.
 * Two boundary lines, which are curved around the edge of the field and connect the two goal-lines. Together, the boundary-lines and the goal-lines mark out the playing area, in a slightly truncated oval.
 * Two goal squares, one at each end of the field, which are 6.4 x in front of each goal-face. The line parallel to the goal line is called the kick-off line. This marks out the area from which a kick-in is taken. 1 player from each team is required to be in each goal square at the beginning of each quarter and after each goal.
 * The imaginary continuation of the kick-off line in both directions is called the nine-metre line; it is not marked, but radial markings outside the boundary line, two at each end of the ground, indicate where the nine-metre line crosses the boundary line. The position of a mark or free kick taken on the defensive side of this line is always advanced to it.
 * Two blue dots, 15 m in front of the centre of each kick-off line, indicating where the man on the mark stands for a kick-in.
 * The centre square, which is 50 x in the centre of the ground.
 * The centre circles: two concentric circles of 3 m and 10 m diameter, with a line bisecting them running wing-to-wing. These markings dictate where the ruckmen and other midfielders can stand during a centre bounce. 1 player from each team is required to be in the centre circle at the beginning of each quarter and after each goal.
 * Two fifty-metre arcs: a circular arc at each end of the field drawn between the boundary lines at a distance of 50 m from the centre of the goal-line, one red-and-white, and one blue-and-white. Originally introduced as a visual indicator of distance only, these markings now dictate starting positions for forwards and defenders at a centre bounce. Some competitions and exhibition games also allow for super goals, which score more points for a goal kicked from long range. 6 players from each team are required to be in each fifty-metre arc, with one of these from each team required to be in the goal square, at the beginning of each quarter and after each goal.
 * Interchange gates: a series of yellow and white markings on the boundary line near the teams' interchange benches, which dictate where players may enter and exit the ground for interchanges.

Grounds at lower or junior levels will lack many of these markings, or paint them in lower detail.

Goal posts


At each end of the ground there are two goal posts, spaced 6.4 m apart, and a further 6.4 m on either side of these are behind posts, 5 m in height. The goal posts are conventionally painted white, and in South Australia, the behind posts are customarily painted red. All posts are typically padded with wall padding to minimise injury due to players colliding with them.

Surface
Due to possible injuries caused to players moving at high speed by marking, jumping, turning and being tackled without protective padding, the playing field standards imply use of lawn as a surface.

Purpose-built stadiums
Almost all Australian rules football fields are of a suitable size and shape for cricket; and in the majority of cases, the fields are used for cricket in the summer and Australian rules football in the winter, a seasonal strategy which is part of the history of Australian sport. As a consequence of this, there are relatively few fields which were purpose-built for and used by Australian rules football to the exclusion of cricket and all other sports. Like the cricket oval, the field is usually referred to and named as an oval.

However, there are numerous grounds – particularly those built more recently – which were built with Australian rules football as the primary intended purpose, but upon which other sports, including cricket, have been played.

Variations
Variations of the standard field dimensions and layout exist. For junior levels, smaller fields are often used. Rectangular fields have also been used in the past in Australia and also overseas, as well as adapted fields from other sports such as association football and American football.